Round axial fan with balancing structure

ABSTRACT

A round axial fan with balancing structure includes a hub, a ring-shaped band located around an outer side of the hub, and a plurality of blades extended between the hub and the ring-shaped band. At least one removable area is defined on the ring-shaped band for serving as a balancing area. By determining and removing one or more balancing areas at appropriate locations from the ring-shaped band, uneven weight distribution of the components of the round axial fan can be adjusted to enable stable rotation of the fan without producing vibration. The provision of the balancing area on the ring-shaped band of the round axial fan also enables reduced material and labor costs for adjusting the weight distribution of the fan.

FIELD OF THE INVENTION

The present invention relates to a balancing structure, and moreparticularly to a round axial fan using such balancing structure toenable quick adjustment of the weight distribution of the round axialfan, so that the round axial fan can rotate stably and the material andlabor costs for balancing the fan can be reduced.

BACKGROUND OF THE INVENTION

Electronic information products, including computers, have now becomevery popular among consumers and provide very wide applications.Consumers' wide demands also lead to rapid technical development in theelectronic information industry. While the current electronicinformation products have increasingly upgraded computing speed andaccess capacity, the heat produced by the components in the electronicinformation products during high-speed operation thereof also increases.To remove the heat produced by the components from the electronicinformation products, heat sinks and cooling fans are usually providedin the electronic information products at positions of heat source.

Cooling fans can be generally divided into two types, namely, axial fansand centrifugal fans. A round axial fan is one type of the axial fans.The round axial fan includes a hub, a plurality of blades radiallyoutward extended from the hub, and a ring-shaped band integrallyconnected to the radially outer ends of the blades. The round axial fanis formed by injection molding. In the process of injection molding,there are times the injection-molding material is not uniformly injectedto thereby result in uneven weight distribution of the hub, the bladesor the ring-shaped band. The uneven weight distribution of the hub, theblades or the ring-shaped band has adverse influence on the balancedrotation of the round axial fan. That is, when the weight distributionof the hub, the blades or the ring-shaped band is uneven, the wholeround axial fan would tilt during rotation to result in abrasion andvibration of the central shaft of the round axial fan relative to thebearing cup of the base supporting the round axial fan. The abrasion andvibration of the central shaft not only produces noise, but alsoaccelerates the fatigue of the central shaft of the round axial fan toshorten the service life thereof. The fan device using the round axialfan would have reduced overall quality and provide poor heat dissipationeffect.

To solve the problem of uneven weight distribution of the round axialfan, there are manufacturers who try to adjust the uneven weightdistribution by locally providing weights on the hub of the round axialfan. FIG. 1 is a perspective view showing a conventional round axial fanwith balancing structure. The conventional round axial fan 10 includes ahub 11 and a ring-shaped band 12. At least one blade 13 is providedbetween the hub 11 and the ring-shaped band 12. The radius of the hub 11relative to a center of the round axial fan 10 is smaller than theradius of the ring-shaped band 12 relative to the center of the roundaxial fan 10. At least one recess 111 is formed on the hub 11. In thecase the round axial fan 10 tilts during rotation due to uneven weightdistribution of the fan 10, weights are directly fitted in correctrecesses 111 to balance the weight distribution of the fan 10. However,since there is a difference between the radii of the hub 11 and thering-shaped band 12, the weights fitted in the recesses 111 on the hub11 must be several times as heavy as the ring-shaped band 12 to reachthe required balance. Therefore, the cost for providing the weights onthe hub 11 is high. Further, with the weights fitted on the hub 11, theround axial fan 10 in rotating is still subject to tilting due to theuneven weight distribution of the ring-shaped band 12 and the largeradius thereof. As a result, the abrasion and vibration of the centralshaft of the round axial fan 10 relative to the bearing cup on the baseof the fan is increased and requires more time and labor to adjust theoverall weight distribution of the round axial fan 10.

In brief, the conventional round axial fan with balancing structure hasthe following disadvantages: (1) By fitting the weights on the hub,increased material for the weights is needed to achieve the purpose ofbalancing the fan; (2) the balance achieved by fitting the weights onthe hub is easily adversely affected by the large radius and the unevenweight distribution of the ring-shaped band; and (3) additional materialand labor costs are required to adjust the weight distribution of theround axial fan.

It is therefore tried by the inventor to develop an improved round axialfan with balancing structure in order to overcome the disadvantages inthe prior art.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a round axialfan with balancing structure, so that the round axial fan can be quicklyadjusted to achieve balanced weight distribution and accordingly stablerotation thereof.

Another object of the present invention is to provide a round axial fanwith balancing structure, so that material and labor costs for adjustingthe weight distribution of the round axial fan can be reduced.

A further object of the present invention is to provide a round axialfan with balancing structure, in which a shielding member is attached toat least one balancing area provided on the fan, so that the function ofthe round axial fan to produce airflow is not adversely affected by thebalancing area when the same is removed from the fan to balance theweight distribution of the fan.

To achieve the above and other objects, the round axial fan withbalancing structure according to the present invention includes a hub; aring-shaped band located around an outer side of the hub to therebydefine an annular flow passage between the hub and the ring-shaped band;a plurality of blades located in the annular flow passage, the bladesrespectively having a radially inner end connected to an outercircumferential surface of the hub and a radially outer end connected toan inner circumferential surface of the ring-shaped band; and at leastone removable area defined on the ring-shaped band for serving as abalancing area. By determining and removing one or more balancing areasat appropriate locations from the ring-shaped band, it is able to adjustan overall weight distribution of the round axial fan for the same torotate stably.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present inventionto achieve the above and other objects can be best understood byreferring to the following detailed description of the preferredembodiments and the accompanying drawings, wherein

FIG. 1 is a perspective view showing a conventional round axial fan withbalancing structure;

FIG. 2 is a top perspective view showing a round axial fan withbalancing structure according to a first preferred embodiment of thepresent invention;

FIG. 3 is a bottom perspective view of the round axial fan withbalancing structure according to the first preferred embodiment of thepresent invention;

FIG. 4 is a sectioned side view of the round axial fan with balancingstructure according to the first preferred embodiment of the presentinvention;

FIG. 5A is a sectioned side view of a round axial fan with balancingstructure according to a second preferred embodiment of the presentinvention;

FIG. 5B is a sectioned side view of a round axial fan with balancingstructure according to a third preferred embodiment of the presentinvention;

FIG. 6A is a top perspective view showing a round axial fan withbalancing structure according to a fourth preferred embodiment of thepresent invention;

FIG. 6B is a bottom perspective view of the round axial fan withbalancing structure according to the fourth preferred embodiment of thepresent invention; and

FIG. 6C is a sectioned side view of the round axial fan with balancingstructure according to the fourth preferred embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described with some preferredembodiments thereof and with reference to the accompanying drawing. Forthe purpose of easy to understand, elements that are the same in thepreferred embodiments are denoted by the same reference numerals.

Please refer to FIGS. 2, 3 and 4 that are front perspective, rearperspective and sectioned side views, respectively, of a round axial fanwith balancing structure according to a first preferred embodiment ofthe present invention. As shown, the round axial fan 20 includes a hub30 and a ring-shaped band 40 located around an outer side of the hub 30to thereby define an annular flow passage 31 between the hub 30 and thering-shaped band 40. The ring-shaped band 40 has a first end face 41 anda second end face 42 respectively located at an upper and a lower sideof the ring-shaped band 40. A radius of the first end face 41 relativeto a center of the hub 30 may be larger than, equal to, or smaller thana radius of the second end face 42 relative to the center of the hub 30.In the illustrated first preferred embodiment, the radius of the firstend face 41 relative to the center of the hub 30 is equal to the radiusof the second end face 42 relative to the center of the hub 30.

In the annular flow passage 31, there is provided a plurality of blades50. The blades 50 each have a radially inner end 51 connected to anouter circumferential surface of the hub 30 and a radially outer end 52connected to an inner circumferential surface of the ring-shaped band40. The blades 50 in rotating are able to guide airflow to move, so asto produce air convection to carry away heat produced by aheat-producing element. On the ring-shaped band 40, there is defined atleast one removable area that can be removed from the ring-shaped band40 to serve as a balancing area 60. A shielding member 61 is attached toan outer surface of the at least one balancing area 60 provided on thering-shaped band 40, so as to effectively stop airflow from enteringinto a void at the balancing area 60 when it is removed from thering-shaped band 40.

The at least one balancing area 60 is defined on the ring-shaped band 40for adjusting uneven eight distribution of the round axial fan 20 whenthe same shows an unbalanced state and/or vibrates while rotating due touneven weight distribution of the hub 30, the ring-shaped band 40 or theblades 50, or between the first end face 41 and the second end face 42of the ring-shaped band 40. The at least one balancing area 60 may bedefined on the first end face 41 of the ring-shaped band 40, as shown inFIG. 2; or be defined on the second end face 42 of the ring-shaped band40, as shown in FIG. 3; or be defined on both of the first and thesecond end 41, 42 of the ring-shaped band 40, as shown in FIG. 4. In theillustrated first preferred embodiment, when uneven weight distributionof the hub 30, the ring-shaped band 40 or the blades 50, or between thefirst end face 41 and the second end face 42 of the ring-shaped band 40is found, one or more of the at least one balancing area 60 atappropriate positions are removed from the ring-shaped band 40 to formone or more holes thereon, so as to adjust the weight distribution ofthe hub 30, the ring-shaped band 40 or the blades 50, allowing the roundaxial fan 20 to be quickly adjusted for rotating in a balanced state. Byperforming the weight distribution adjustment on the ring-shaped band 40instead of the hub 30, the number of required balancing areas 60 can beeffectively reduced to achieve the purpose of saving the labor andmaterial costs for adjusting the weight distribution of differentcomponents of the round axial fan 20. Further, the condition of a tiltedround axial fan 20 during rotation thereof caused by non-uniform radiusand weight distribution of the hub 30 and the ring-shaped band 40 can beavoided to enable further saving of the material and labor costs.

FIG. 5A is a sectioned side view of a round axial fan with balancingstructure according to a second preferred embodiment of the presentinvention. In the second preferred embodiment, a radius of the first endface 41 relative to a center of the hub 30 can be larger than a radiusof the second end face 42 relative to the center of the hub 30 accordingto actual need, and the at least one balancing area 60 is defined on thefirst end face 41. Alternatively, according to a third preferredembodiment of the present invention as shown in FIG. 5B, the radius ofthe second end face 42 relative to the center of the hub 30 can belarger than the radius of the first end face 41 relative to the centerof the hub 30 according to actual need, and the at least one balancingarea 60 is defined on the second end face 42. By determining andremoving one or more balancing areas 60 at appropriate locations fromthe ring-shaped band 40, the uneven weight distribution of the hub 30,the ring-shaped band 40 or the blades 50, or between the first end face41 and the second end face 42 of the ring-shaped band 40 can be adjustedfor the whole round axial fan 20 to rotate in a balanced manner.

FIGS. 6A, 6B and 6C illustrate a fourth preferred embodiment of thepresent invention. Since the components and the connection relationtherebetween in the fourth embodiment are generally similar to those inthe previous embodiments, they are not repeatedly described herein.However, the fourth embodiment is different from the previousembodiments in that the first end face 41 and the second end face 42include a first radially outward extended end flange 411 and a secondradially outward extended end flange 421, respectively; and the at leastone balancing area 60 is defined on the first end flange 411 at thefirst end face 41 of the ring-shaped band 40 as shown in FIG. 6A, or onthe second end flange 421 at the second end face 42 of the ring-shapedband 40 as shown in FIG. 6B, or on both of the first and the second endflange 411, 421 at the first and the second end face 41, 42 of thering-shaped band 40, respectively, as shown in FIG. 6C. When thebalancing area 60 is removed from the first and/or the second end flange411, 421 for the purpose of adjusting the weight distribution of the hub30, the ring-shaped band 40 or the blades 50, or between the first endface 41 and the second end face 42 of the ring-shaped band 40, a notchis formed on the first and/or the second end flange 411, 421 to achievethe same function of adjusting the overall weight distribution of theround axial fan 20 for the same to rotate in a balanced manner.

In conclusion, the round axial fan with balancing structure according tothe present invention has the following advantages: (1) by defining thebalancing area or areas on the ring-shaped band, the labor and materialcosts required to adjust the weight distribution of different componentsof the round axial fan can be reduced; (2) by defining the balancingarea or areas on the ring-shaped band to adjust the weight distributionof different components of the round axial fan, it is able to avoidadverse influence on the balance of the round axial fan by the largeradius and uneven weight of the ring-shaped band; (3) the materialneeded for balancing the round axial fan can be saved; (4) the laborcost for balancing the round axial fan can be reduced; and (5) theservice life of the round axial fan can be prolonged.

The present invention has been described with some preferred embodimentsthereof and it is understood that many changes and modifications in thedescribed embodiments can be carried out without departing from thescope and the spirit of the invention that is intended to be limitedonly by the appended claims.

1. A round axial fan with balancing structure, comprising a hub; aring-shaped band located around an outer side of the hub to therebydefine an annular flow passage between the hub and the ring-shaped band;a plurality of blades located in the annular flow passage, the bladesrespectively having a radially inner end connected to an outercircumferential surface of the hub and a radially outer end connected toan inner circumferential surface of the ring-shaped band; and at leastone removable area defined on the ring-shaped band for serving as abalancing area; whereby, by determining and removing one or morebalancing areas at appropriate locations from the ring-shaped band, anoverall weight distribution of the round axial fan can be adjusted toenable stable rotation of the fan.
 2. The round axial fan with balancingstructure as claimed in claim 1, wherein the ring-shaped band has afirst end face and a second end face separately located at two oppositesides of the ring-shaped band.
 3. The round axial fan with balancingstructure as claimed in claim 2, wherein the first end face and thesecond end face include a first and a second radially outward extendedend flange, respectively.
 4. The round axial fan with balancingstructure as claimed in claim 2, wherein the at least one balancing areais provided on the first end face.
 5. The round axial fan with balancingstructure as claimed in claim 2, wherein the at least one balancing areais provided on the second end face.
 6. The round axial fan withbalancing structure as claimed in claim 2, wherein the at least onebalancing area is provided on both of the first and the second end face.7. The round axial fan with balancing structure as claimed in claim 3,wherein the at least one balancing area is provided on the first endflange at the first end face, and a notch is formed on the first endflange when the balancing area is removed therefrom.
 8. The round axialfan with balancing structure as claimed in claim 3, wherein the at leastone balancing area is provided on the second end flange at the secondend face, and a notch is formed on the second end flange when thebalancing area is removed therefrom.
 9. The round axial fan withbalancing structure as claimed in claim 3, wherein the at least onebalancing area is provided on both of the first and the second endflange at the first and the second end face, respectively; and a notchis formed on each of the first and the second end flange when thebalancing area is removed therefrom.
 10. The round axial fan withbalancing structure as claimed in claim 2, wherein a radius of the firstend face relative to a center of the hub is equal to a radius of thesecond end face relative to the center of the hub.
 11. The round axialfan with balancing structure as claimed in claim 2, wherein a radius ofthe first end face relative to a center of the hub is larger than aradius of the second end face relative to the center of the hub.
 12. Theround axial fan with balancing structure as claimed in claim 2, whereina radius of the second end face relative to a center of the hub islarger than a radius of the first end face relative to the center of thehub.
 13. The round axial fan with balancing structure as claimed inclaim 1, further comprising a shielding member attached to an outersurface of the at least one balancing area.